Over-Subscription Rates

Over-Subscription of Gemini Telescope Time

The figure below show the average (weighted by
partner share) over-subscription of the Gemini telescopes between semesters 2005B and 2014A. The over-subscription shown on the left axis is calculated as the ratio of the total Gemini time requested to the total advertised available science time. Requests for
Exchange time are not included. The available Gemini science time includes all three
science bands 1, 2 and 3, and the requested time does not include program calibrations. Starting in 2013A, the UK is no longer a
Gemini partner, increasing the amount of time available to the other partners by about 20%.

Typically the Observatory executes about 65% of the advertised science time in the Call for Proposals, the remaining time going primarily to
weather loss. Currently, the available time advertised in the
Call for Proposals
is filled to the 80% level with classical and queue bands 1, 2 and 3 programs, to avoid overfilling the queue and disappointing band 3 investigators.
Poor weather programs
are designed to use any remaining very poor but useable telescope time.

Allowing for the 80% queue filling factor and adding a 9% overhead for calibrations at Gemini North, and 5% for Gemini South, for the typical instrument distributions, the effective over-subscription rate is 1.4 times the values shown in the plots below for Gemini North, and 1.3 times the value for Gemini South. The values along the right axis show the effective over-subscription rate allowing for calibration overheads and the 80% queue filling factor; currently Gemini North is over-subscribed by about a factor of three and Gemini South about a factor of two.

The
Demand for Gemini Telescope Time page shows the demand in number of hours, without the division by available time.
The over-subscription for each partner, calculated as described above, is also available. Note that the y-axis scales differ - the upper limit is 5 for partners Australia, UK and US, and 3.5 for partners Argentina, Brazil and Canada, and for the host institutions and Gemini staff.

Figure 1: Average over-subscription of Gemini North and South telescope time between semesters 2005B and 2014A, calculated as described above. The drop in subscription rates for the South in 07B can be attributed to the loss of
GNIRS. The effective over-subscription rate is 1.4∗ the values shown for Gemini North, and 1.3∗ the values shown for Gemini South, as the queue is filled to 80% to reflect
typical semester loss rates and calibration overheads are not included. Values along the right axis show the effective oversubscription rate, 1.35∗ the values on the left axis.

Argentina

Figure 2: Over-subscription of Gemini North and South telescope time between semesters 2005B and 2014B, for partner Argentina. The over-subscription is the ratio of the total requested time to the total available science time in classical and bands 1, 2 and 3 for the partner, as advertised in
each semester's Call for Proposals. The effective over-subscription rate is 1.4∗ the values shown for Gemini North, and 1.3∗ the values shown for Gemini South, as the queue is filled to 80% to reflect
typical semester loss rates and calibration overheads are not included.

Australia

Figure 3: Over-subscription of Gemini North and South telescope time between semesters 2005B and 2014A, for partner Australia. The over-subscription is the ratio of the total requested time to the total available science time in classical and bands 1, 2 and 3 for the partner, as advertised in
each semester's Call for Proposals. The effective over-subscription rate is 1.4∗ the values shown for Gemini North, and 1.3∗ the values shown for Gemini South, as the queue is filled to 80% to reflect
typical semester loss rates and calibration overheads are not included.

Brazil

Figure 4: Over-subscription of Gemini North and South telescope time between semesters 2005B and 2014A, for partner Brazil. The over-subscription is the ratio of the total requested time to the total available science time in classical and bands 1, 2 and 3 for the partner, as advertised in
each semester's Call for Proposals. The effective over-subscription rate is 1.4∗ the values shown for Gemini North, and 1.3∗ the values shown for Gemini South, as the queue is filled to 80% to reflect
typical semester loss rates and calibration overheads are not included.

Canada

Figure 5: Over-subscription of Gemini North and South telescope time between semesters 2005B and 2014A, for partner Canada. The over-subscription is the ratio of the total requested time to the total available science time in classical and bands 1, 2 and 3 for the partner, as advertised in
each semester's Call for Proposals. The effective over-subscription rate is 1.4∗ the values shown for Gemini North, and 1.3∗ the values shown for Gemini South, as the queue is filled to 80% to reflect
typical semester loss rates and calibration overheads are not included.

Gemini Staff

Figure 6: Over-subscription of Gemini North and South telescope time between semesters 2005B and 2014A, for Gemini Staff. The over-subscription is the ratio of the total requested time to the total available science time in classical and bands 1, 2 and 3 for the staff, as advertised in
each semester's Call for Proposals. The effective over-subscription rate is 1.4∗ the values shown for Gemini North, and 1.3∗ the values shown for Gemini South, as the queue is filled to 80% to reflect
typical semester loss rates and calibration overheads are not included.

Hosts: Chile and the University of Hawaii

Figure 7: Over-subscription of Gemini North and South telescope time between semesters 2005B and 2014A, for the Gemini South host Chile and the Gemini North host University of Hawaii. The over-subscription is the ratio of the total requested time to the total available science time in classical and bands 1, 2 and 3 for the host, as advertised in
each semester's Call for Proposals. The effective over-subscription rate is 1.4∗ the values shown for Gemini North, and 1.3∗ the values shown for Gemini South, as the queue is filled to 80% to reflect
typical semester loss rates and calibration overheads are not included.

UK

Figure 8: Over-subscription of Gemini North and South telescope time between semesters 2005B and 2012B, for partner UK. The UK is no longer a partner in 2013A. The over-subscription is the ratio of the total requested time to the total available science time in classical and bands 1, 2 and 3 for the partner, as advertised in
each semester's Call for Proposals.The effective over-subscription rate is 1.4∗ the values shown for Gemini North, and 1.3∗ the values shown for Gemini South, as the queue is filled to 80% to reflect
typical semester loss rates and calibration overheads are not included.

US

Figure 9: Over-subscription of Gemini North and South telescope time between semesters 2005B and 2014A, for partner US. The over-subscription is the ratio of the total requested time to the total available science time in classical and bands 1, 2 and 3 for the partner, as advertised in
each semester's Call for Proposals. The effective over-subscription rate is 1.4∗ the values shown for Gemini North, and 1.3∗ the values shown for Gemini South, as the queue is filled to 80% to reflect
typical semester loss rates and calibration overheads are not included.